Key guard



June 2, 1931. T. w. KUPFER KEY GUARD Filed Feb. 6, 1931 [N VENTOR EmmM/fuP/z-R A ORNE Y Patented June 2, 1931 JUNITED STATES THEODORE W.KUPFER, OF ROCHESTER, NEW YORK KEY GUARD Application filed February 6,1931.

* look and prevent it from being dislodged thru the key hole from theoutside in an attempt to unlock the door from without.

One of the objects of the invention is to p provide an extremelysimplified construction in order to make 1t inexpensive to manufacture.

Another object of the invention 1s to provide an improved and simplifiedmethod of fastening the key guard to the door which {:5 makes itpossiblefor anyone to attach it in a minimum length of time.

Another object of the invention is to provide a construction andoperation for the locking member of the guard which makes itextremelysimple to' operate.

Other objects and attendant advantages will become more readily apparentfrom the detailed description of one embodiment of the invention whichfollows, reference being had to the accompanying drawings in whichFigure 1 is a front elevation of a portion of a door with the door lockhaving my improved key guard attached thereto.

Figure 2 is an end elevation of the portion 9 of the door and door lockwith the key guard attached to it.

Figure 3 is'a vertical sectional view of the key guard, the sectionbeing taken on the line 3m8w of Figure 2.

Figure 4 is a vertical sectional view of the key guard and portion ofthe door, the section being'taken on the line 4a;4w of Figure 1. V v

Figure 5 is a horizontal sectional view of the key guard, the sectionbeing taken on the'line 5w5a2 of Figure 4.

In'the several figures of the drawings like reference numerals indicatelike arts.

The key guard forming the subject matter of my present invention is soconstructed that it combines simplicity of construction with simplicityof operation and when attached to the door forms'a permanent fixturewhich cooperates with the lock in such an efficient manner that itprevents any attempt to un- Serial No. 513,914.

lock the door from the outside as long as the key is inserted into thelock on the inside of the door.

As illustrated in the several figures of'the drawings the key guardcomprises a vertical bracket 1' which has the locking plate 2 pivoted atthe upper end thereof. The vertical bracket 1 has a rearwardly extendingor offset lug 3 formed at the lower end thereof and in this lug isprovided a suitable hole thru which passes the screwl that fastens thelower end of the bracket 1 to the door below the escutcheon.

The upper end of the bracket 1 is provided with a central slot 5 and atthe bottom of this slot is struck up a rearwardly extending hook shapedlug 6 which is adapted to hook over the bottom edge of the key hole 7provided in the escutcheon. When attaching the key guard to the door thelug 6 is first hooked into the key hole so that it engages the bottomedge thereof as above pointed out,

The lug thus locates and anchors the upper portion of the bracket 1 inplace on the escutcheon plate and with the addition of the screw 4firmly holds the key guard permanently in place on the door.

Two eyes 8 and 9 are formed at the top of the vertical bracket 1, ineach of which is mounted a pivot pin 10. These pivot pins extend to oneside and have at their outer ends the eyes 11 and 12 pivoted thereon.The eyes'll and 12 are formed on the inner end of the locking plate 2and thus provide the pivotal means with which the locking plate 2 ismounted to swing on the vertical bracket 1.

At the rear of the bracketl along each side thereof are provided theguides 13 and 14. A slide is mounted at the back of the bracket 1 andits edges engage into the guides 13 and 14 and are guided in'a straightline movement thereby. The slide 15 carries a pin 16 which projects thrua slot 17 in the bracket 1 and carries on the outside thereof thecombined knob and latch 18.

The slide 15 located at the back of the bracket 1 is provided at the topwith a hook shapedlug 19 and into this lug engages the endof thebowspring 20. The bowspring 20 is bent and placed into the back of thebracket 1 so as to normallylift the slide 15 and thus yieldingly holdthe combined knob and latch 18 in its elevated position. As illustratedin Figures 2, at and 5 the inside of the top of the combined knob andlatch 18 is slightly cut away at 21 to present an angular flat, surfacewith which the outer end of the locking plate 2 engages to hold itin itsinoperative position. In order b0 bring the locking plate intothisinoperative position it is swung down from the horizontal positionillustrated in Figures 1 and 2 until the outer end of the locking platestrikes the curved outer surface of the combined knob and latch. Byforcing the locking plate against the knob 18, the knob is depresseduntil the outer end of the locking plate has moved from the curved frontof the knob to the cut away rear 21 thereof which allows the knob 18 tobe forced up again by its spring 20 and thus hold the locking plate 2 ina vertical position in front of the bracket 1. v

The locking plate is spring operated and when released by the combinedknob and latch 18 immediately swings outwardly and upwardly against thekey so that the yielding pressure exerted by the locking plate holds thehandle of the key in a horizontal position from which it cannot beturned until the locking plate is again moved away from it. The springfor operating the locking plate in this manner is an extension of thebow spring 20 which, as illustrated in Figure 3, extends upwardly and isfirst wound around one of the pivot pins 10 and then looped with theloop 23 over the back of the locking plate 2 to the other of the pivotpins 10. After being wound around the second pivot pin it extends downalong the back of the bracket 1 where its end is bent at right angles soas to engage and anchor itself behind the guides 13 and 14. In order toshow the spring clearly, especially the loop 23 thereof, the lockingplate 2 is shown in dotted lines in Figure 8 in a position in line withthe bracket 2. This figure also shows that the locking plate 2 is alsoslotted in the middle and that the slot in the locking plate 2 forms acontinuation of the slot in the bracket 1. As these slots are locateddirectly in front of the key hole in the escutcheon the web of the keyis free to be inserted or withdrawn from the key hole when the lockingplate is placed in its inoperative position illustrated in full lines inFigure 4L and in dotted lines in Figures 1 and 2. After the key has beeninserted and has been turned to lock the lock, the bow or handle thereofis placed in an approximately horizontal position. The locking plate 2is then released by depressing the combined knob and latch 18. The loop23 of the spring which operates the locking plate then forces thelocking plateto swing outwardly and upwardly untilv it rests against theunder side of the key and yieldingly holds it in a horizontal position.The pressure of the spring is sufiicient to prevent a turningof the keyfrom the outside of the door so that it cannot be pushed out of the lockand the lock opened from the outside by means of a duplicate key orother instrument designed for opening locks.

I claim:

' 1. A key guard comprising a vertical bracket with a centralslot in theupper end thereof, a rearwardly projecting hook shaped lug at the bottomof said slot adapted to engage over the lower end of the key hole in anescutcheon and anchor the upper end of said bracket in place in front ofthe escutcheon, fastening means for fastening the lower end of saidbracket below the escutcheon plate to anchor said bracket, and a springpressed locking plate mountedzto swing on the upper end of said bracket.

2. A key board comprising a -vertical bracket, a spring operated lockingplate mounted 011 said bracket, combined anchoring and locating meansfor anchoring and locating said bracket to the escutcheon with relationto the key hole therein, and fastening ineans for fastening said bracketin place below the escutcheon.

3. A key guardcomprising a vertical bracket, a latch plate mounted toslide at the back of said bracket, a latch carried by said latch plate,a locking plate mounted to swing on said vertical bracket, said lockingplate being adapted to be held in its inoperative vertical vposition bysaid latch and spring pressed means for swinging said lockingplate fromits inoperative position into engagement with the key on the releasethereof by said latch.

1. A key guard for a lock having an escutcheon with a key hole thereinand comprising a vertical bracket, anchoring means for anchoring saidbracket to said escutcheon and locate the said bracket in apredetermined position in front of said escutcheon with relation to thekey hole provided therein, fastening means on said bracket to fastensaid bracket in place below said es cutcheon and prevent thedisengagement of said anchoring means from said escutcheon, a springpressed locking plate mounted to swing on said bracket and springpressed latching means for holding said locking plate in an inoperativevertical position in'front of said bracket, said spring pressed lockingplate being adapted to swing into engagement with the handle of a keylocated in the key hole when released by said latching means to hold thehandle of the key in a predetermined position and hold the key againstaxial movement in the key hole.

5. A key guard for a lock having an escutcheon' with a key hole,comprising a vertical bracket having aslot in the upper end thereof, arearwardly projecting hook shaped lug at the bottom of said slot andadapted to engage over the bottom of said key hole, fastening means atthe bottom of said bracket to fasten said bracket in place below saidescutcheon and hold said hook shaped lug in place in said key hole, alatch plate mounted to slide in back of said vertical bracket, a latchcarried by said lat-ch plate, a locking plate having a slot at the innerend thereof and mounted to swing on said vertical bracket with its slotin line with the slot in said vertical bracket, spring pressed means forswinging said locking plate outwardly into engagement with the key holeto yieldingly hold said key against axial movement in said key hole, andspring pressed means for yieldingly holding said latch plate to havesaid latch engage the outer end of said locking plate when swung awayfrom the key into a downwardly vertical position in front of saidbracket.

THEODORE W. KUPFER.

